#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<math.h>
int main() {
	double n = 0.00;
	int m = 0;
	while (scanf("%lf %d", &n, &m) != EOF) {
		double sum = 0.00;
		for (int i = 0; i < m; i++) {
			sum += n;
			n = sqrt(n);
		}
		printf("%.2lf\n", sum);
	}
	return 0;
}